If you click on a cell while it's displaying multiple cells exposed by a single click, it treats it as if you clicked on the cell it's currently considering for display. If that cell is unoccupied it can go unnoticed, but if it's occupied it kills you.

beastie wrote:Please double-check that this is happening, and provide details of your system and circumstances if possible.

Macbook Pro, Tiger 10.4.9, and it's definitely happening. The only way to ameliorate it is to turn off "reveal animation delay". It is possible that the event is occurring during the reveal animation, or that the click is getting handled immediately after the animation. You may need to set a flag before the animation starts, clearing it afterwards, and ignore clicks that occur when that flag is set.